Add AlertPresentable that absracts an alert presenter.

Riot/Modules/Common/Alert/AlertPresentable.swift

@@ -0,0 +1,36 @@
+// 
+// Copyright 2021 New Vector Ltd
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+
+import Foundation
+
+/// AlertPresentable absracts an alert presenter
+protocol AlertPresentable {
+    
+    func showError(_ error: Error, animated: Bool, completion: (() -> Void)?)
+    func show(title: String?, message: String?, animated: Bool, completion: (() -> Void)?)
+}
+
+// MARK: Default implementation
+extension AlertPresentable {
+    
+    func showError(_ error: Error) {
+        self.showError(error, animated: true, completion: nil)
+    }
+    
+    func show(title: String?, message: String?) {
+        self.show(title: title, message: message, animated: true, completion: nil)
+    }
+}